change deprecated render :text to render :plain in rails 5

app/controllers/admin/feeds_controller.rb

@@ -100,7 +100,7 @@ class Admin::FeedsController < OrbitAdminController
 				end
 			end
 		end
-		render :text => 'success'
+		render :plain => 'success'
 	end
 	def announcements
 		@filter_fields = {}